I think bulldozer is a great term, because it also captures the 'creative destruction' that occurs when the new better thing replaces the old thing, like google

I think bulldozer is a great term, because it also captures the 'creative destruction' that occurs when the new better thing replaces the old thing, like google replacing altavista / yahoo, facebook replacing myspace and so on, the iPhone replacing the iPod for the most part and so on. Also all the other terms I've heard so far are not catchy.